This invention relates to a trim tab actuator for a marine propulsion device and more particularly to an automatically activated trim tab device that improves steering accuracy and permits greater maneuverability.
It is well known that many types of watercraft and powered by outboard drives that are pivotally supported for steering movement about a generally vertically extending steering axis. Such outboard drives may comprise either outboard motors or the outboard drive portion of an inboard-outboard drive. Although this type of steering arrangement is particularly advantageous due to its simplicity, there are some instances when the steering movement accomplished by the mere pivotal movement of the outboard drive is insufficient to achieve the desired accuracy and speed in changing course.
The use of trim tabs in connection with outboard drives for effecting the steering of the outboard drive is well known. For example, one form of trim tab arrangement employs a trim tab that is pivotally supported on the outboard drive and which is steered in an opposite direction from the outboard so as to create a hydrodynamic force that assists in the steering movement. Although such devices are effective in providing light steering, they do not improve the accuracy of the steering and can, in some instances, deteriorate the amount of steering control. This deterioration in steering control can be objectionable in certain conditions, for example, when trying to steer in stormy weather or when traversing difficult terrain wherein numerous obstacles must be steered around.
There are also provided arrangements wherein a trim tab is employed for assisting in keeping the watercraft on course. Again, such devices are particularly advantageous for their intended purpose. However, these types of devices also do not aid in providing effective and quick change of course.
It is, therefore, a principal object of this invention to provide an improved trim tab actuator for a marine propulsion device.
It is a further object of this invention to provide a trim tab actuator for a marine propulsion device wherein the trim tab is automatically steered to maintain good steering control.
It is a further object of this invention to provide an automatically controlled trim tab actuator for improving steering sharpness and speed of response.